A line set consists of two copper pipes that connect the indoor air handler to the outdoor condenser, carrying the refrigerant. These are essential components found in our Installation Kits. To keep the exterior of your home looking neat, many professionals use Line Set Covers to hide the piping. The length of the line set can impact the efficiency and capacity of the system. One pipe carries the cold liquid refrigerant, while the other carries the hot gaseous refrigerant. Proper insulation of these lines prevents energy loss and condensation issues.